考虑滑移效应的钢-混组合梁非线性有限元研究

Nonlinear Finite Element Analysis of Steel-concrete Composite Beam Considering the Slip Effect

混凝土桥面板和钢梁之间的剪力连接件能协调混凝土翼板和钢梁的变形,保证钢梁和混凝土桥面板产生组合效应共同工作,但绝对刚性的连接件并不存在,无论是完全剪力连接还是部分剪力连接都存在纵向界面滑移。纵向界面滑移使截面的实际弹性弯矩小于采用换算截面法的弯矩计算值,同时使构件的挠度和应变增大,所以不考虑纵向滑移就不能真实、准确地反映组合梁的受力性能。基于Newmark几何模型,将混凝土板和钢梁以及剪力连接件按一整体单元考虑,采用T.L列式增量法,推导了考虑纵向滑移效应的非线性钢-混组合梁单元模型,并描述和定义了所采用的组合梁各个构件的材料非线性本构关系,最后通过算例验证了所推导方法的准确性。

Shear connectors between the concrete bridge panel and steel beam can coordinate the deformations produced by steel beam and concrete wing, and ensure the steel and concrete bridge panel to produce a combined effect of common work. But absolutely rigid connections do not exist, either full shear connection or partial interac- tion exist longitudinal interface slip. The longitudinal interface slip will make the section actual elastic bending mo- ment smaller than the moment of transformed-section method, while the deflection and strain increase, so it cannot truly reflect the behavior of the composite beams without considering the interface slip. Based on Newmark geomet- ric model, considering the concrete slab,steel beam and shear connectors as a whole element, and making use of the T. L. formulation, a nonlinear composite beam element model was developed which had taken the longitudinal interface slip effect into consideration. The material nonlinear constitutive relation of each component in composite beam element model was also described and defined. At last several numerical examples were computed to validate the accuracy of proposed approach.